1. Field of the Invention
The present invention relates to blister packages for medicaments; and more particularly, to such blister packages which are child-resistant.
2. Description of the Prior Art
Medicaments are commonly marketed in blister packages. Blister packages typically have a thermoformed blister layer which is generally planar except in the areas where blisters are formed. Adhered to the underside (i.e., the side away from the blister formations) of the thermoformed layer is a rupturable layer which is utilized to seal a medicament within the blister. To remove a medicament from the package, a force is applied to the blister which forces the medicament through the rupturable layer, thereby freeing the medicament from the package. Unfortunately, such blister packages are not child-resistant.
Various approaches have been utilized to render blister packages for medicaments child-resistant. Typically, a non-rupturable layer is laminated to the blister layer such that it prevents the medicament from being forced through the rupturable layer until the non-rupturable layer is rendered ineffective.
One common approach to rendering the nonrupturable layer ineffective is to enable the nonrupturable layer to be peeled from the blister package. Peeling of the nonrupturable layer is often enabled by extending the nonrupturable layer past the blister layer such that a grasping tab is provided. Alternatively, peeling is often enabled by including a line of weakness in the blister layer such that upon breaking the blister layer along the line of weakness a grasping tab is provided.
Another common approach to rendering the nonrupturable layer ineffective involves utilizing an oriented film for the rupturable layer which, although being resistant to rupturing, is relatively easily torn in the direction of orientation. A slit is typically included through the blister package such that the package can be torn through the blister releasing the medicament.